By-Pass Starting
Starting a tractor while standing on the ground beside the machine is not a safe
procedure. To do this, the operator must either make certain electrical connections on the
starter motor, or reach up and over to turn the ignition key. An operator standing on the
ground cannot be sure if the transmission is in neutral or in park.
If a manual transmission is in gear when the engine is by-pass started, the tractor
probably will run over the operator. The tractor will start moving as soon as the engine
starts to turn over. There may be a slight delay if the tractor has either a hydrostatic
transmission or power-shift type transmission, but the delay will not be sufficient for
the operator to get out of the way.
New tractors are sold with a shield covering the starter motor to prevent by-pass
starting. Many older tractors did not have this shield. Now, a retro-fit shield that
covers the by-pass contacts and prevents by-pass starting is available. This shield should
not be removed from the starter motor except for servicing the starter motor, then
replaced immediately.
Front-End Loader Incidents
Front-end loaders are used for many jobs in agriculture, essentially lifting and moving
objects and materials. These versatile implements are often misused by stretching their
lifting capacity, inappropriate use, and lack of safety equipment.
Heavy objects such as big round bales, mini-bulk containers, farm machinery parts, and
other items are often lifted with front-end loaders. There is a limit to how much a loader
can safely lift. The limit may be affected by condition of hydraulic lines and hoses,
pressure capacity of the hydraulic pump, proper ballasting of the tractor, strength of
front axle assembly, and condition of front tires. The owner/operator of a loader-equipped
tractor is usually knowledgeable about its condition and capacity, but caution and good
judgement must always be applied.
Adequate ballasting of the loader-equipped tractor is essential for safe lifting. If
the rear of the tractor is somewhat light and bouncy as the loader starts to lift the
load, additional ballasting is needed. At this point, the safe operator will not proceed
with lifting, but will lower the load and safely add ballast to the rear of the machine.
Agricultural workers have been fatally crushed as a result of attempting to move big
round bales with a front-end loader not equipped with grapple forks. The grapple forks
grasp the big round bale and prevent it from rolling rearward, out of the bucket and down
the arms of the loader toward the operator. The safe worker always selects a grapple fork
equipped front-end loader to move big round bales and lifts the load high only when it
needs to be. Another choice would be a spear type bale mover, mounted on either the front
or rear of the tractor.
Speed -- working too fast for existing conditions -- is often a factor in front-end
loader injury-incidents. An elevated front-end loader raises the center of gravity of the
unit, making it easier to tip due to momentum and/or centrifugal force. Always keep the
load and the speed low when using the front-end loader.
The front-end loader is not intended or designed for lifting people for any type of
work. There are no safety features to provide support for people while in the bucket.
System controls are not designed for safe movement of a loader bucket with a person in it.
Rearward Tractor Rollovers
Tractor rollovers happen when the center of gravity moves past a baseline of stability,
either to the side or the rear of the machine. The center of gravity must be kept within
the baseline of stability to keep the tractor right side up.
Agricultural tractors will easily tip to the rear when the rear wheels cannot rotate
enough to move the machine forward. As the front of a tractor rises and rotates opposite
to the rear axle, momentum and engine power work together to keep the tractor body
rotating and lifting. The process of a rearward tractor rollover can take as little as
three fourths of a second, less than the reaction time of the average worker.
Five situations where this can happen are when:
- the tractor is stuck in mud or snow, preventing the rear wheels from rotating.
- the rear wheels cannot turn because chains, boards, or other materials are used to
improve traction and actually prevent the wheels from rotating.
- the tractor is climbing a hill that is too steep. The steeper the hill, the more the
risk.
- the clutch is released too quickly with the transmission in a lower gear and the engine
running at a high speed.
- a load is hitched above the drawbar of the tractor.
Improper Hitching
Many agricultural workers are injured or killed as a result of improper hitching of a
tractor to a load. Loads for pulling should be hitched only to the drawbar or the
three-point hitch. There is no place on the rear of a tractor that is safer, or more
effective for pulling, than the drawbar.
Loads that are attached by looping a chain around the axle housing, seat base, or upper
link of the three-point hitch reduce the pulling capacity of the tractor and increase the
possibility of a rearward tractor rollover.
The drawbar mounted on a three-point hitch system can be moved up and down to fit many
situations, but the safest situation is when the drawbar is at the height recommended in
the operator's manual. Raising this drawbar decreases safety and pulling effectiveness of
the tractor. Stay braces should be installed where possible to maintain a safe drawbar
height.
Rearward tractor rollovers can be prevented by:
- releasing the clutch only when the rear wheels CAN rotate forward.
- using a reverse gear to break tractor tires from frozen conditions.
- choosing NOT to climb steep hills in a forward direction with a tractor.
- using a reverse gear to back the tractor up a steep hill where it is feasible.
- using only enough engine speed to start the tractor moving and using the clutch
smoothly.
- changing tractor speed gradually by applying power smoothly.
- ballasting the tractor properly for the work to be done.
- appropriate use of tire chains, boards and other materials to improve traction of wheels
that are slipping.
- hitching loads properly to the drawbar.
Sideways Tractor Rollovers
Similar to rearward tractor rollovers, sideways roll-overs happen when the center of
gravity of the machine passes over one of the baselines of stability. Three situations
most common for sideways rollovers are:
- when the tractor is driven on a hillside that is too steep
- when the front-end loader is elevated too high for a given load on a hillside that is
too steep or in a turn at excessive speed
- when the tractor is driven too close to the edge of a roadside ditch or other steep
slope.
The wider the tractor (from outside edge to outside edge of the rear wheels) the more
stable the machine is for any given angle of tilt to the side. Also, as the center of
gravity is more centrally located within the baseline of stability, the more stable it is.
Proper ballasting of the tractor will help to keep the center of gravity low and safely
centered.
The operator is responsible for keeping the tractor's center of gravity within its
baseline of stability. To do this, he/she must decide and react accordingly; when is a
side hill tilt too steep for the tractor, and when is an elevated load is too high for a
given speed? The safe operator is always aware of the operating environment and safely
alters his/her driving to match those ever-changing conditions.
ROPS -- Roll Over Protective Structures
It is nearly impossible to buy a new tractor without a ROPS already installed, along
with seat-belts. Much of the used-tractor market is filled with ROPS-equipped tractors.
But many farms and ranches have a ready supply of older tractors without ROPS. Many of
them can be equipped with a retrofit ROPS, but the value of the tractor isn't considered
enough to warrant the expense. A more important question is, does the life of the operator
who drives that tractor warrant the expense of the ROPS?
An important part of the ROPS is the seat belt that keeps the operator within the
safety envelope. Wearing the seat belt, even when working fields as flat as a tabletop,
will help prevent poor posture in the seat and ease back strain. The seat belt works, but
only if it is worn.
Some tractors are used in situations where the full height of a ROPS would be an
inconvenience to the work being done. Foldable ROPS are now available on most new
tractors. They should be folded only when needed to enter or clear an overhead
obstruction. When the ROPS is in the folded position the seatbelt should not be worn since
the ROPS is not effective in that position. Always secure the ROPS in the upright position
as soon as possible after the close clearance work is done.
Falls From Tractors
Many agricultural workers have suffered wrist, arm, hip, leg, and ankle injuries as a
result of falling from their tractors. Most of these falls are due to unsafe, improper
mounting and dismounting the steps of the tractor. The steps on the tractor should be used
the same as the steps of a ladder; either two hands and one foot or one hand and two feet
should be in contact with the steps at all times. Climbing the steps with no hands holding
on or taking two steps at a time is inviting an injury-incident.
The operator should always face the tractor when going up or down the steps - the
handholds will then always be in position to be used; otherwise they are in back of the
worker and out of reach. Many pants cuffs or boot loops have caught on the clutch pedal as
the operator moves forward off the platform, pitching him/her forward, off the tractor.
This can be prevented simply by facing the tractor when going up or down the steps and
using the handholds.
Extra Riders
Extra riders are never safe on a tractor. There is no place for them to stand or sit
safely. There is no seatbelt to keep the rider in an envelope of safety if the tractor
should tip over. Many children have fallen from tractors as an extra rider, even from cabs
with supposedly locked cab doors. Many falls from a tractor result in injury or death; the
rear wheel is right there, ready to fatally crush the fallen extra rider.
Tractor Runovers
Tractor runovers often happen due to:
- the driver's inability to see small children and other people in the line of travel.
- extra riders falling from the steps, cab, or drawbar.
- backing the tractor toward machinery to be attached.
- by-pass starting.
These injury-incidents happen and are preventable.
A child or unseen adult in the vicinity of the tractor is at risk of being run over.
The operator must be sure the area is clear before moving the tractor. Children should not
be permitted to play in the area where tractors and other machinery are operating.
Children should be restricted to a safely fenced play area.
Tractors should be driven responsibly at all times, but especially when near populated
areas such as the farm buildings. The operator should always drive the tractor and
machinery at a safe speed for the given situation. Also, keep the brake pedals locked
together for simultaneous braking of the rear wheels in these areas.
The time saved by operating the tractor at a higher rate of speed in potentially
populated areas (the farmstead) is simply too little to justify risking human life. Reduce
the speed, and be cautious when people are present.
Caught-Between Crushing
Backing up to attach machinery
Agricultural workers can easily become crushed between a tractor and the machinery
being attached. The worker is standing between the tractor and the machine as the operator
is backing up the tractor. There is either a breakdown of communication or control of the
tractor is lost; the worker on the ground is in the wrong spot, the tractor moves rearward
too much, or the tractor operator cannot see the worker, who is then crushed between the
machines.
The safe solution to this situation is, the worker should not enter the area between
the tractor and the machine until the tractor has been stopped, shifted into neutral, and
the brakes applied. The worker should step out of the area between if adjustments have to
be made between the tractor and the machine, particularly if the tractor has to be closer
to the machine.
Articulated four wheel drive tractors
The area between the front and rear wheels on either side of an articulated four wheel
drive tractor is a very dangerous place. Slight movement of the steering wheel will cause
the tractor to move or articulate in the middle, bringing the front and rear wheels of one
side or the other closer together with more than enough power to crush a human.
If the steering wheel of some tractors is moved, even with the engine not running, the
tractor will articulate later when the engine is started. Not all four wheel drive
tractors are so closely coupled between front and rear sections that a crush will happen,
but it is an area to stay out of as much as possible, especially when the engine is
started or running.
PTO Stub Shaft Entanglement
Most tractors, new or old, have a PTO stub shaft protruding from the rear. All newer
and most older tractors were equipped with a PTO master shield to cover the stub shaft.
Most of these shields are difficult to remove, but some have been. This leaves the stub
shaft exposed and puts the operator at risk of entanglement with it.
Many tractors are equipped with stub shaft shields that cover the entire stub shaft
when not in use. These shields usually screw into place and are often misplaced soon after
being removed. Tractors are often found with this shield missing. If this shield is
missing, it is to the operator's advantage to replace it and restore another safety
feature of the tractor. Refer to NDSU Extension Service Circular AE-1070, Straight Facts
About PTO Shafts and Shields, which discusses the dangers of exposed PTO shafts.
Master shields for PTO stub shafts should never be removed from the tractor except for
maintenance work, and then should be replaced immediately after. Stub shaft shields should
never be taken off except when the PTO stub shaft is to be used and replaced immediately
after PTO use.
Tractor Operator Responsibilities
The farm tractor is not a machine that can be operated safely without responsibility on
the part of the driver. There are eight primary responsibilities the safe tractor operator
must meet whenever the tractor is used. They are:
- conducts proper maintenance
- conducts pre-operation checks
- avoids injury-incident situations
- maintains safety features
- uses tractor as intended
- refuels safely
- starts and stops safely
- adjusts the tractor for safety
The safe worker will recognize dangerous situations and make changes to remove the
hazard. He/she will not proceed with work until it is safe to do so, knowing and believing
that no job is so important that injury or human life should be at risk.
Maintaining the Safety Features
The safety-oriented owner/operator of a farm tractor maintains all of the safety
features on it. Not all tractors have the same or equivalent safety features when new. The
safe owner/operator will add safety updates to machinery as they become available.
Safety features to be maintained on agricultural tractors relate to the following:
- tractor stability
- tractor visibility and recognition
- safety decals
- operator comfort and control
- protection from hazards
Safety features include ROPS (rollover protective structure) with seatbelt,
posture-designed seat, lighting for highway and field, SMV (slow moving vehicle) sign,
flashing amber hazard lights, turn signals, fenders, engine shrouding, PTO master shield,
PTO stub shaft shield, manual override power steering, neutral start interlocking switch,
steps with handholds, hazard warning decals, and breakaway hydraulic couplers.
Tractor operators need to know these features and how they work, as well as how to use
them and maintain them. Safety features that have been allowed to deteriorate and become
ineffective are a hazard. The operator assumes the protection is there, depends on it and
is at greater risk if it is missing.
Owners and operators of tractors need to know that it is their responsibility to
maintain safety decals in good condition. Owners are responsible for providing safe
equipment for their employees. The decals are there to provide important safety
information about the tractor and its safety features. The decals can't do their job if
they cannot be read; replace them as they wear out due to weather and use.
Prevention of Injury-Incidents
Of the many tractor injury-incidents that happen, few are caused by machinery or
equipment failure. Most are caused, directly or indirectly, by carelessness and
unnecessary hurry. Use safe procedures, pay attention to what is being done and how it is
being done, and THINK about what you are doing -- then tractor safety isn't too difficult
or time-consuming.
Additional Information
Safe Operation of Agricultural Equipment, 2nd Revision, 1990, Hobar Publications, St.
Paul, MN
FMO Agricultural Safety, Third Edition, 1996, Deere & Company, Moline, Illinois
Agricultural Tractor Safety on Public Roads and Farms, A Report To The Congress from
The Secretary of Transportation, 1971, U.S. Government Printing Office, Wash. D.C.
AE-1121, February 1997
